Volume 57, Waitangi, 1995

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“Sustainability” is a social construct, and is difficult
to define in precise value-free terms. It has
ecological (biophysical) and socio-economic
dimensions. Biophysical indicators are tools that
can be used to define resource status. They cannot
directly measure sustainability, but are useful for
comparing present resource status with defined
limits set within a socio-economic framework. We
measured vegetation and soil variables in 4 areas
of grazed North Island hill country with different
management (fertiliser application/stocking rate)
histories (1973 to 1994) and sub-divided into 36
paddocks. Nineteen vegetation (including herbage
production); soil chemical, physical and biological;
and soil water variables were selected as potentially
useful biophysical indicators. Analysis of the results
for these variables suggested that pasture botanical
composition (especially content of high-fertility
responsive grasses and of herbaceous weed species)
and earthworm mass/unit area explained most of
the variance of the data matrix. These variables
were also highly correlated with herbage production,
an indicator of likely economic performance.
Development of the most suitable indicators
requires good understanding of agro-ecosystem
function, and is hampered by our lack of
understanding of critical processes.
Keywords: biophysical indicators, hill country,
pasture, soil, sustainability

Building a solid foundation for pasture production in Northland: P, K, S and
lime requirementsA.H.C. ROBERTS, J.D. MORTON, M.B. O’CONNOR and D.C. EDMEADES

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The generally strongly weathered, leached soils of
Northland consist of four major soil groups. The
yellow-brown earths and podzols and yellow brown
sands are formed from sedimentary rocks, while
brown granular clays and red and brown loams are
formed from volcanic rocks. In terms of the
relationship between pasture production and
fertiliser nutrient requirements, for both sedimentary
and volcanic soils, the production functions
are shown to be of the “diminishing returns” type,
and the point at which near-maximum production
(97%) occurs is defined as the “biological
optimum” soil test level. Biological optimum test
values for sedimentary and volcanic soils are: Olsen
P 20 and 22; quicktest K 6 and 7; sulphate-S 10;
organic-S 15; and pH 5.9. Once biological optimum
soil test levels have been attained then maintenance
fertiliser nutrient rates are appropriate. In order to
move up the pasture production curve an average
of 7 and 11 kg P/ha above maintenance will increase
Olsen P by 1 unit for Northland sedimentary and
volcanic soils respectively. Similarly, on average
60 kg K/ha will raise quicktest K by 1 unit on
volcanic soils, but capital requirements for K on
sedimentary soils in Northland are not known. An
average of 35 and 25 kg S/ha will correct S
deficiencies on sedimentary and volcanic soils.
Keywords: biological optimum, lime, Northland,
nutrient requirements, phosphorus, potassium,
sedimentary soils, sulphur, volcanic soils

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Eleven cereal rye (&cafe cereale) cultivars, one
triticale (Triticum secale) and one winter wheat
(Triticum aestivum) cultivar were evaluated in 2
studies for their ability to extend the grazing season
into the autumn and winter in southern Ohio. The
cultivars, 5 in 1993 and 9 in 1994, were randomly
assigned to replicated plots and planted in late
summer. Plots were harvested in late autumn to
determine dry matter (DM) yield and forage quality.
Results from the two years indicate significant
differences (P=O.O5) between cultivars for DM
yield, crude protein(CP) and NDF levels. DM yields
ranged from 1389 to 2470 kg/ha (1993) and 1018
to 2 124 kg/ha (1994). Crude protein levels ranged
from 25.2 to 27.9% (1993) and 28.8 to 33.7%
(1994). A second harvest of the 1994 plots was
made in early spring 1995 for continued evaluation.
Statistically significant differences again existed
between the stockpiled cultivars. DM yields ranged
from 1979 to 2980 kg/ha while crude protein levels
ranged between 21.5 and 27.0% of DM. Results
support the conclusion that selected cereal rye
cultivars can produce excellent yields of high
quality forage for late autumn and winter grazing
in the Ohio climate.
Keywords: cereal rye, extended grazing season,
Secale cereale, triticale, wheat

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The results are briefly reported of seven comparative
studies on aspects of pasture and animal
performance from pastures based on Yorkshire fog
(Holcus Zanatus), perennial ryegrass (Lofiurn
perenne) or tall fescue (Festuca arundinacea)
grown under adequate soil nutrient conditions (e.g.,
Olsen P 20-30 pg/g) and under continuous or
rotational stocking by sheep. Pasture production,
as measured by the stocking rate required to
maintain specified sward conditions, was 2.5%
greater on perennial ryegrass than on Yorkshire
fog pastures, and 25% greater on Yorkshire fog
than on tall fescue. Differences in liveweight gain
and wool production in weaned lambs between
pastures were relatively small and inconsistent, but
levels of worm egg output were lower for lambs on
Yorkshire fog than on tall fescue. The use of
polyethylene glycol to bind condensed tannins
reduced performance slightly in lambs on Yorkshire
fog and tall fescue, but not those on perennial
ryegrass.
Keywords: condensed tannins, Festuca arundinacea,
Holcus lanatus, lamb growth, Lolium
perenne, wool production

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Three experiments were conducted in Hawke’s Bay
to evaluate the agronomic effectiveness of DAF’
slurry fertilisers containing finely ground
diammonium phosphate (DAP). The experiments
also compared the effectiveness of sulphur (S)
applied as sulphate and as elemental S. Experimental
sites, all on dryland yellow-grey earth soils
on permanent sheep pasture which had not received
fertiliser for several years, covered a range of soil
fertility, pasture species and chemical composition.
Trials were open to grazing, and exclusion cages
were used to measure herbage production over 1
or 2 years. No difference in yield (PrO.05) was
recorded for DAP applied at low rates either as a
slurry or as a conventional solid fertiliser. It was
concluded that grinding of DAP into small particles
and its application as a slurry had no effect on the
agronomic performance of the applied nutrients
when compared with solid fertiliser. DAP slurry
fertilisers had no statistically significant effect on
herbage dry matter production, dry matter
digestibility, protein content, or trace element
content relative to unfertilised control pasture.
Application of DAP slurry twice at annual intervals
had no significant (PrO.05) effect on soil test
measurements. Sulphate S was more effective than
elemental S in overcoming S deficiency in these
experiments.
Keywords: diammonium phosphate, fertilisers,
fertiliser forms, Hawke’s Bay, slurry fertilisers,
sulphur

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Subtropical grasses can be a significant component
of northern North Island pastures. Several annual
and perennial types with different functional
characteristics are widely established, allowing a
range of different climatic, soil and moisture
situations to be colonised. Many of the species
have persistent seed banks or vegetative propagation
facilitating long-term persistence.
Biochemical types associated with moist conditions
arc most common but types associated with arid
conditions are also represented. Abundant rainfall
at temperatures above 25“C, and factors which
reduce temperate grass productivity (lowered soil
fertility and winter/spring grazing damage) appear
to favour higher proportions of both annual and
perennial subtropical grasses such as summer grass
and paspalum. Grazing pressure and timing, and
level of fertiliser inputs appear important for species
such as ratstail and carpet grass in less productive
sites; The nature of competitive interactions
between subtropical (C,) species and temperate
(C,) species is poorly understood and invertebrate
herbivory can be important in altering the balance
between these species. An analysis of present
subtropical grass species distributions in northern
districts of New Zealand indicates that knowledge
of the underlying species biological characteristics
is useful in predi’cting subtropical grass abundance.
To predict likely problem years and to develop
management strategies to minimise problems, a
better understanding is needed of the effects of
climate on subtropical grass abundance in temperate
pastures and competitive interactions. There may
be scope for developing improved varieties for dry
areas.
Keywords: C,, C,, climate, competition, ecology,
grazing, pasture, subtropical grasses, temperate

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Growth of five New Zealand white clover cultivars,
Grasslands Kopu, Grasslands Pitau, Grasslands
Huia, Grasslands Tahora and Prop, was quantified
at differing soil moistures in both the field and the
glasshouse. The first trial employed a rain-out
shelter to impose two soil water treatments. While
there were no differences among the cultivars for
leaf water status, there were differences in plant
growth parameters in response to water deficit.
Water deficit did not significantly affect leaf
appearance rate of Prop, although there was a 2-
fold difference. There was, however, a 3.5- to 6-fold
decrease in leaf appearance rate due to water deficit
for the other cultivars. Water deficit did not
significantly reduce leaf size for the medium- and
small-leaved cultivars Huia, Tahora and Prop; but
was halved for Kopu and Pitau. Prop had the lowest
stolon growing point survival under water deficit
and Pitau the highest. Leaf longevity was greatest
for Prop and least for Pitau when grown under
optimum water supply, but this pattern was reversed
under water deficit stress. The second trial, a pot
trial, investigated the response of the same five
cultivars to three different soil water regimes
(control, mild and severe stress). The growth
parameters of smaller-leaved cultivars, particularly
Prop, were less affected than the large-leaved
cultivars in their response to water deficit. These
short-term trials showed that some small-leaved
cultivars of white clover have an ability to adjust
their growth and habit in response to water deficit
more effectively than large-leaved cultivars. Prop
was able to maintain a higher leaf appearance rate
than other cultivars when grown under water deficit.
However, while exhibiting this drought tolerance
adaptation the low stolon growing point survival
of Prop could result in a poor recovery from
drought. Small-leaved cultivars are rarely taprooted,
a characteristic of plants adapted to more
prolonged drought conditions. The probability of
combining these characteristics and improving
summer production of white clover through
identification of drought tolerance is discussed.
Keywords: cultivars, drought, Trifolium repens,
variation, water deficit

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Results from the MRDC-ANZ monitor farm
programme in the Far North (Omatua Farm Ltd)
have involved the adoption or continued use of onfarm
technologies such as crossbreeding, yearling
mating, regrassing, supplementary feeding,
subdivision, fertiliser use, stock policy evaluation
and monitoring animal growth rates. These results
have substantially improved farm productivity and
profitability. Farm business planning has been a
significant part of the monitor farm process, leading
to a 12% increase in yearly beef produced off the
monitor farm. Small farms like Omatua Farm Ltd
make up 63% of the beef cattle and sheep farms in
the Far North District Council. The potential of the
farm monitor-business planning approach on these
farms is to improve gross annual income by
$20 000. Without improvements in productivity
and profitability an increasing amount of beef cattle
farm land in the area is likely to end up in an
alternative land use.
Keywords: business planning, farm management
technologies, monitor farm, small beef cattle farms

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The effects of 10 years of nil or maintenance
phosphorus (P) fertiliser (250 kg/ha/yr superphosphate)
on pasture production and composition,
and on soil P status, were measured in a farmlet
trial on hill country near Te Kuiti. Withholding P
resulted in 29-35% less annual pasture production
and 54-72% less legume (predominantly white
clover) production. There was little difference in
seasonality of production between the two farmlets.
The loss in production in the nil P farmlet was
predictable based on the decline in soil Olsen P
test to 6-8 ppm and the results from past mowing
trials. Additional soil measurements revealed that
soil organic P levels were increasing at the site and
this will have contributed to the decline in plantavailable
P in soil. Re-application of P at 23 kg/ha
markedly increased legume growth (by 180-330%)
in the nil P farmlet, which was proportionally twice
as high on steep slopes as on easy slopes. This
response in legume production was most evident
in summer at a time when improved feed quality is
valuable for finishing lambs. Indeed, legume growth
in the P re-application plots exceeded that in the
maintenance P farmlet by 23-28%. This reflected
reduced plant-available soil N status due to less
inputs from N, fixation in the previous 10 years,
and thereby increased the competitive advantage
of legumes over grasses where P deficiency was
diminished by fertiliser re-application.
Keywords: fertiliser history, hill country, legume
production, pasture production, phosphorus,
seasonality, soil phosphorus

Evaluation of a beef growth model for use in beef finishing decisionsM.D. ROLLO, D.G. MCCALL, C.J. BOOM and G.W. SHEATH

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A decision support computer program for beef
finishing, called BoVision, is described. It is based
on biological models of animal and pasture growth,
and is designed to assist the user in making strategic
and tactical decisions about their beef finishing
operation. Examples of its uses are to answer
questions regarding profitability of l-year versus
2-year-old cattle policies, the optimum stocking
rate, and the profitability of local trade versus prime
versus bull beef. BoVision can also be used to
evaluate premiums required for out-of-season beef,
the economics of nitrogen use and supplementary
feeding. It can also be used to perform sensitivity
analyses. An important aspect of the program’s
development process was the involvement of a
group of beef finishing farmers. The animal growth
and pasture intake models used are presented. This
paper backgrounds the program’s development, and
evaluates its use in predicting Angus steer performance
for a trial conducted at Whatawhata
Research Centre. Performance for a Friesian bull
trial is also evaluated. Implications for BoVision’s
use on farms are discussed.
Keywords: animal growth, beef finishing,
computer model

Evaluation of a meadow fescue (Festuca pratensis) population from NorthlandB.M. COOPER

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Meadow fescue (Festuca pratensis Huds.) is not
commonly. recognised as a significant pasture
species in New Zealand. On a Northland dairy
farm near Kaitaia a population of meadow fescue
was increasing and providing significant feed in
drought years. Meadow fescue ecotype seed lines
from Kaitatia were collected and compared for
relative vigour to Grasslands Supernui perennial
ryegrass (Lolium perenne), Grasslands Wana and
Grasslands Kara cockSfoot (Dactylis glomerata),
Palaton and Venture reed canary grass (Phalaris
arundinacea) and Grasslands Advance tall fescue
(Festuca arundinacea). Variation occurred within
the 22 meadow fescue lines in terms of early growth,
4 lines being superior to Advance tall fescue during
winter and spring. Overseas lines failed to persist.
Vigour of remaining lines declined as the trial
progressed, Persistent meadow fescue plants
remained small and were slow to tiller. Overseas
meadow fescue introductions had no endophyte
present, but local lines contained Acremonium
uncinatum which does not produce the mammalian
mycotoxins Iolitrem B and ergovaline. Unless a
specific role for the species can be determined
further work is largely unjustified, as productivity
did not surpass that of control species. Animal
health relationships with different endophytes
warrant further,jnvestigation.
3
Keywords: Dactylis glomerata, ecotypes,
endophytes, ‘Festuca arundinacea, Festuca
pratensis Huds., Lolium perenne, Northland,
Phalaris arundinacea

Farmer perspectives on sustainable farmingJ.H. COTMAN

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Waikato Federated Farmers has recently taken a
proactive role in land management issues which
has involved developing for farmers an operational
definition of sustainable farming and ways of
promoting and demonstrating sustainable practices
on farm. In partnership with AgResearch and
Environment Waikato, the operational definition,
management practices and user friendly indicators
to aid monitoring were obtained, Sustainable
farming recognises socio-economic goals of farmers
(viable business, enjoyable lifestyle, good living
standards, good short term profitability, satisfied
farmers) and resource goals (efficient, contented
animals, productive pasture, clean water, control
of feral pests, unrestricted market access, adequate
rural services, family heath). Grazing guidelines
have been produced using the above information
and on-farm study groups set up to demonstrate
these practices in a whole-farm system. Userfriendly
indicators have also been developed and
are in use.
Keywords: farming goals, guidelines, participatory
process, sustainable farming

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The direct effects of fungal endophyte-produced
alkaloids on dairy beef cattle were determined in
early summer 1992 and in autumn of 1993 and
1994. Endophyte level (nil vs high) or strain (wildtype
vs selected 187BB) did not affect liveweight
gain (LWG), but in 1994 weaners on nil endophyte
consumed more dry matter than those on either
endophyte treatment. The presence of clover
enhanced LWG, reflected in higher dry matter
intake in autumn 1993. Under the severe endophyte
challenge of 1994, clover reduced the severity of
ryegrass staggers even though the daily intake of
lolitrem B was higher in the presence of clover.
Under the rotational grazing management contrast
imposed in 1994, followers had lower LWG than
leaders and tended to have higher daily intake of
lolitrem B. Grazing management effects on ergovaline
intake were inconsistent and differed between
endophyte strain and clover level. Animal responses
to endophyte strain under contrasting conditions
during each measurement period were related to
daily alkaloid intake when scaled to liveweight. It
is concluded that under the environmental conditions
experienced in the Manawatu, endophyte
alkaloids have minimal direct effect on cattle
performance, although the reduction in ryegrass
staggers by clover presence and its elimination by
using a selected endophyte have important practical
effects. Indirect effects through pasture production,
composition or persistence may be more important
to animal performance.
Keywords: alkaloid intake, cattle, endophyte,
ergovaline, herbage intake, liveweight gain, lolitrem B, peramine

Making sense of the link between tiller density and pasture productionC. MATTHEW, A. HERNANDEZ-GARAY and J. HODGSON

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Interpretation of tiller or shoot density data requires
resolution of two independent, confounding effects,
namely size/density compensation and what is here
called the “leaf area effect”. Size/density compensation
implies that at higher herbage mass,
individual tillers or shoots are larger, but the
population density is correspondingly decreased.
The leaf area effect represents difference in sward
leaf area for two tiller populations. Such leaf area
differences may be environmentally or genetically
determined, but must of necessity be expressed
through change in tiller size and/or tiller density as
“yield components” of leaf area. The theoretical
basis for distinguishing between size/density
compensation and the leaf area effect is to consider
tiller or shoot density and herbage yield,
respectively, as X,Y co-ordinates in a size/density
plot. When such a plot is drawn on a logarithmic
scale, points along a line of -l/2 slope show size/
density compensation with respect to each other.
Movement of points to the right or left of the size/
density compensation line is evidence of a leaf
area effect. It is shown that when the size/density
effects are removed from a data set in this way,
rankings of experimental treatments for the leaf
area effect can often be reversed compared with
the ranking of uncorrected tiller density. Tiller
density data corrected for size/density compen-.
sation in this way appear to be a useful indicator of
sward productivity.
Keywords: sizeldensity compensation, sward
productivity, tiller density

Management and productivity of white clover in a kikuyu grass sward in
subtropical AustraliaW.J. FULKERSON and M. REEVES

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This plot-cut study, on heavy clay soil, evaluated
the establishment, productivity and persistence of
Haifa white clover (Trifolium repens) in a vigorous
sward of kikuyu grass (Pennisetum clandestinum).
Defoliation treatments were 5 or 12 cm stubble
height in spring and 14 days or “when ready”
(lower leaves beginning to senesce) in spring and
autumn. Over the 2t/2 years of the study and under
optimal defoliation treatment (5 cm stubble height
in spring and at the “when ready” defoliation
interval in spring and autumn), total yield of forage
was 19 952 kg DMfha/yr, of which 57% was white
clover. The reason for the loss of vigour of white
clover in year 3 is not clear. It may have been due
to the heavy infestation of the root knot nematode
Meloidogyne or to defoliation management over
the second summer, or both. Management at the
transition phases between the two pastures (early
autumn and late spring) is critical to success and
is explained in the light of farmer experience.
Keywords: defoliation management, Pennisetum
clandestinum, subtropics, Trifolium repens

Management of summer feed deficits on three high-performing dairy farms in
the ManawatuD.I. GRAY and J.C. LOCKHART

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New Zealand dairy farmers rely on pasture grazed
in situ to feed their herds. Summer is the most
difficult period to manage because pasture production
is usually highly variable and, in most
years, less than herd requirements. Dairy farmers
can use a range of options (e.g., summer forage
crops, silage) to minimise the impact of both
variable and inadequate summer feed supply. Much
has been written about recommended procedures
for planning and monitoring pasture-based systems,
but there is little documentation on the processes
actually used by New Zealand dairy farmers. To
this end the summer management processes of three
high-performing Manawatu seasonal supply dairy
farmers were studied over 4 years. The farmers
used management systems based on their experience.
A range of simple techniques was used to
identify potential feed deficits. The farmers then
used a set of decision rules to select the best option
or combination of options to overcome feed deficits.
The study highlighted the potential benefits that
could accrue from integrating farmer knowledge
with scientific knowledge.
Keywords: dairy farmers, decision-making, farmer
knowledge, monitoring, summer management

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The fundamental influence of variation on the
production of quality products is reviewed. The
partitioning of this variation into that which is
controllable on the farm and that which is
uncontrollable on the farm is discussed. The
effectiveness of an on-farm quality assurance
programme depends on the level of variation in a
trait than can be controlled by farm management
practices. A simple graphical tool that can be used
on farm and is suitable for monitoring performance
through time is the cusum control chart. This chart
plots the cumulative sum of deviations from target
performance. It is designed to identify the
occurrence of problems in production on farm for
which effective management action may be taken.
The operation of a cusum chart for monitoring a
quality assurance programme on farm is illustrated,
using as an example the control of ultimate muscle
pH in cattle. The cusum chart in this example is
designed and operated using measurements
supplied by a meat processor which were made on
the muscle following slaughter.
Keywords: controllable variation, cusum chart,
farm monitoring, quality assurance, uncontrollable
variation

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Farm monitoring on sheep and beef cattle farms in
Northland has been in operation for the past 8
years. The emphasis has been on monitoring the
performance of sheep and beef cattle farms to
provide the data to encourage group members to
make decisions based on objective measurements.
Monitor groups were initially supported by
extension and science personnel with more recent
groups being operated on a commercial basis. Key
biological indices such as animal numbers, weights,
weight gain, meat and wool production and pasture
production are monitored. Group members are
encouraged to use information from the monitor
farm to identify opportunities on their own farms
for improvement in production and income.
Significant gains have been made in production
but it can take 3 to 5 years for the full benefit to be
realised. Pasture production information has been
v,ital to identify changes in feed supply from year
to year during the monitoring programme. Farm
monitoring in the future is likely to be the basis on
which farmers will be able to. meet year-round
supply of product based on specifications of weight,
date and carcass attributes.
Keywords: beef and cattle, farm monitoring,
objective measurement, pasture production, sheep

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Abstract
Inputs and losses of nitrogen (N) were determined
in dairy farmlets receiving nominally 0, 200 or
400 kg N/ha/yr as urea at Dairying Research
Corporation No. 2 dairy, Hamilton. In year 1, N,
fixation by white clover was estimated by r5N
dilution at 212, 165 and 74 kg N/ha/yr in the 0,
200 and 400 N treatments respectively. Removal
of N in milk was 76, 89 and 92 kg N/ha in the 0,
200 and 400 N farmlets respectively. Loss of N
into the air by denitrification was low (6-15 kg
N/ha/yr), and increased with N application.
Ammonia loss into the air was estimated by
micrometeorological mass balance at 15, 45 and
63 kg Nlhalyr in the 0, 200 and 400 N treatments
respectively. Most of the increase in ammonia loss
was attributed to direct loss after fertiliser
application. Leaching of nitrate was estimated
using ceramic cup samplers at 1 m soil depth, in
conjunction with lysimeters, to be 74, 101 and
204 kg NlhaJyr during the second winter when
rainfall and drainage (55@-620 mm) were relatively
high. Nitrate-N concentrations in leachates
increased gradually over time in the 400 N
treatment to an average of 37 mg/l during the
second winter, whereas the corresponding values
for the 0 and 200 N treatments were 12 and 18
mg/l. Preliminary measurements of groundwater
suggest that :ihe nitrate-N concentration is
increasing under the 400 N farmlet relative to the
other two farmlets. Thus, the 400 N treatment had
a major effect by greatly reducing N, fixation and
increasing N losses, whereas the 200 N treatment
had relatively little effect on N, fixation or on
nitrate leaching. However, these results refer to
the first 18 months of the trial and further
measurements are required over time to determine
the longer-term effects of these treatments,
particularly on nitrate levels in groundwater.
Keywords: ammonia loss, dairying, denitrification,
groundwater, leaching, nitrogen fertiliser, N,
fixation

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Estimates of age and weight at mature size are
required for the development of decision-support
and mathematical models to describe beef growth.
Interim results from an experiment designed to
quantify the liveweight gain of steers from weaning
to mature size are reported in this paper. Three
groups of 28 steers have been fed for 2 years from
weaning (8 months) to 32 months of age on the
following treatments: resident, ryegrass-white
clover based pasture (R); a high quality pasture
option based on annual ryegrass in winter and
spring, and red clover and lotus in summer and
autumn (HQ); and a 70% maize grain : 30% silage
diet offered under feedlot conditions (F). Average
daily gains from weaning to 30 months of age and
liveweight at 30 months were 0.69 kg/hd/day, and
709 kg, 0.78 kgfhdlday and 772 kg, and 0.91
kglbdlday and 858 kg for R, HQ and F treatments,
respectively. Feedlot steers had a greater fat depth
over the 12113th rib than either of the pasture fed
treatments, when measured at the same age. In
addition, both pasture groups have shown
seasonality in liveweight gain, with periods of low
liveweight gain in late autumn and winter of the
second and third years. Results are discussed in
relation to the nutritional contrasts between
treatments.
Keywords: feedlot, cattl.e, liveweight gain,
potential growth

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A study was undertaken to ascertain the possible
nutritional impact of subtropical grass invasion into
pastures, by chemically analysing five common
subtropical grasses. Leaves taken from kikuyu
(Pennisetum clandestinum), paspalum (Paspalum
dilatatum), smooth witchgrass (Panicurn
dichotomiforum), crowfoot (Eleusine indica), and
summer grass (Digitaria sanguinalis) were
collected from grassland in the North Auckland,
Waikato and Manawatu regions. Leaves of
perennial ryegrass (Lolium perenne) were also
taken from each pasture as a reference temperate
grass. Relative to perennial ryegrass the subtropical
species clearly showed increased levels of neutral
detergent fibre (NDF; 38.4% vs 57.5%) but reduced
levels of total protein (23.0% vs 13.2%), soluble
sugar (11.7% vs 5.9%) and in vitro organic matter
digestibility (OMD; 84.0% vs 66.6%). Similar
results were obtained for grasses grown in each of
the three areas. Of the subtropical grasses, summer
grass was of the highest nutritive value and crowfoot
was of the lowest. The results of an in vitro rumen
protein degradation experiment showed net
ammonia produdtion from pasture fermentation was
significantly lower for the subtropical species than
for perennial ryegrass. The present study indicates
that the subtropical grasses are of considerably
lower nutritive value than perennial ryegrass. Their
cont.inued spreading into grazing pastures will
probably substantially decrease the nutritive value
of the pastures and animal production.
Keywords: nutritive value, subtropical grasses

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To increase milk productivity on an SO-hectare
dairy farm, a series of improvements was introduced.
With the use of fodder flow analysis and
step-by-step identification of each part of the
farming process a system was introduced on the
property to improve overall output. A new farm
management system was introduced for the
property: The system hinges around the use of
annual ryegrass summer forage crops to achieve a
change to a new ryegrass species, removing old
swards of fescue and kikuyu. Improved soil fertility
and use of nitrogen, together with a crop programme,
helped change the grass growth curve.
Having employed these processes of change, timing
of management decisions and long-term planning
were critical to any change of farm management.
Deciding hew to implement a change and actually
achieving the change were critical to the success of
lifting milk production while maintaining overall
profitability.
Keywords: dairy farms, decision making, farm
management, fodder, nitrogen, profit, research

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Pasture silage is harvested from surplus spring
pasture on many New Zealand dairy farms, for use
as a supplementary feed in times of feed shortage.
Targets for the quality of silage suitable for feeding
to lactating dairy cows are presented, as
recommended by a silage workshop held in Hamilton
in 1994. National information from the Lincoln
University Analytical Laboratory are presented that
show that pasture silage made in the 1994J95 season
was well preserved. However, most of that
silage had a feed quality below the target set for
lactating dairy cows. Averages for DM digestibility
were 65.5-67.9%, estimated M/D was 9.3-9.6
MJ ME/kg DM, and crude protein was 14.6 15.1%.
Silage-making practices were analysed, based on
silage samples entered in the 1994195 Livestock
Improvement Advisory silage competition. The key
to making high quality pasture silage in the 1994/95
season was to harvest pasture by the first week in
November. Nitrogen fertiliser may be used to produce
early surplus pasture without restricting the
feed supply to grazing cows. Further survey work
is planned to confirm observations made, and expand
on practical recommendations for making
high quality pasture silage.
Keywords: dairying, feed analysis, nitrogen
fertiliser, pasture, silage, silage additives

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Four turnip cultivars, two Swede, and one each of
kale, rutabaga and Chinese-cabbage turnip hybrid
were evaluated for their usefulness in extending
the grazing season. The three replicates were
planted on 28 July 1994 and harvested on 31
October and 3 November 1994. Dry matter yields
ranged from 5460 kg/ha for Premier kale to 8877
kg/ha for Rondo turnip. Rondo turnip total yield of
DM was significantly higher (P=O.O5) than all other
cultivars except Doon Major Swede. Crude protein
levels ranged from 8.5% to 24.3% for the tops and
5.9% to 13.4% for the bulbs, with NDF fibre levels
of 17.6% to 21.4% for tops and 15.6% to 20.4%
for the bulbs. All cultivars survived temperatures
of -1O’C with Premier kale being the most winter
hardy, surviving the winter minimum temperature
of -21°C. Forage brassicas can provide high levels
of quality forage for the late autumn and early
winter period, significantly extending the grazing
season in Ohio and the midwest US.
Keywords: brassica, Chinese cabbage-turnip
hybrid, grazing season, kale, rutabaga, Swede, turnip

Performance of setaria in the northern North Island
C.J. BOOM and G.W. SHEATH

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Setaria sphacelata is a perennial C, grass that has
high potential summer yield, but its persistence
and cool-season production are poor. An experiment
investigated whether a winter oats cover crop
could negate these poor traits. While oversowing
oats into established setaria increased total
winter-spring herbage production, the use of a
cover crop reduced setaria persistence despite
minimum soil temperatures being 1.5”C higher.
Starch and soluble sugar levels in three different
leaf and stem fractions of setaria were low and
showed little seasonal variation. S. sphacelata and
S. neglecta plants that had survived previous
evaluations were transplanted into a field nursery
and screened for a further 3 years. From this
nursery, blocks of four phenotypically different
lines were then established and their performance
(herbage production and quality) was assessed for
2 years. Mean annual yields of the more productive
blocks were 12.5 t /ha, 60% of this occurring during
January-March. Herbage quality was assessed as
being low-medium, leaf in vitro digestibilities and
crude protein being 70% and 12% respectively.
Within this “persistent” population, soluble sugars
in the basal fractions of the plant appear important
in assisting cool-season persistence. The place of a
perennial C, grass such as setaria in farm systems
was investigated using the computer model
Stockpol. A smsll specialist block of setaria may
have merit for feeding breeding stock where there
is a need to miriimise the risk of drought in northern
zones of New Zealand.
Keywords: carbohydrates, cover crop, forage
quality, persistence, Setaria spp.

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The dissolution rate of Sechura phosphate rock
(particle size 75-150 pm) was determined at 95
New Zealand sites with a range of soil and
environmental properties. Rates ranged from 0 to
70% of the phosphate rock dissolved per year with
an average dissolution rate of 3 1 %/year. An initial
model based on stepwise linear regression analysis
indicated that the rate of dissolution was negatively
associated with soil pH and positively associated
with rainfall and exchangeable soil magnesium.
There was also an effect of soil type and drainage.
The amount of residual RPR accumulated from
previous fertiliser application can be determined
by a new soil test. This, together with the dissolution
rate estimated from the nature of the RF’R and the
soil and site factors, can be used to indicate likely
soil P status.
Keywords: dissolution, fertiliser, phosphorus,
reactive phosphate rock, soil test

Pre- and post-weaning growth of beef calves reared by cows on one of five
lifetime nutrition levelsD.C. SMEATON, J.B. CLAYTON and A. MALTHUS

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The hypothesis that currently recommended
liveweights for beef cows are too high was tested
at Whatawhata Research Centre. Industry claims
have been that high levels of reproductive efficiency
can be achieved with cows running up to 20%
lighter than current targets, and eating proportionately
less pasture. We ran 150 Hereford x
Friesian cows on 1 of 5 lifetime feeding levels or
treatments. Average liveweights of the five
treatments ranged from 470 to 390 kg at mating
but pregnancy rate was not affected. Calf weaning
weight was affected, however (P

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A study is described which shows the need for a
system to collect data that give farmers market
signals related to meat quality, to enable them to
make decisions on how best to achieve good returns
from their animals. A case study is presented for
one of eight Northland farms where on-farm
handling, nutritional factors and transport factors
that may affect meat quality has been monitored.
The high variability of meat quality parameters
between mobs from four farms is highlighted. For
beef quality to improve, quality must be measured,
and benefits to farmers and meat processing plants
must be based on the quality of the product. A
value-based payment system is strongly advocated,
an essential requirement of which would be a beef
trading database. Five main groups are identified
which would provide input to the database: the
seed-stock industry, commercial cattle breeders,
cattle finishers, meat processors, and meat
exporters. A national standard for describing beef
quality is urgently required and is a prerequisite
for any database.
Keywords: beef quality, case study, database, meat
quality, monitor farms

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Heat stress in Northland cattle has been shown to
be similar to tall fescue toxicosis as described in
south-east USA, but incidence has not been
correlated with the presence of tall fescue on farms.
Tall fescue toxicosis results from grazing
endophyte-infected tall fescue, and is caused by
the alkaloid ergovaline. Cases are described of
cattle suffering typical symptoms of ergovaline
poisoning, though they had negligible access to
tall fescue. Pasture surveys have shown ergovaline
levels in ryegrass pastures to often be sufficient to
cause toxicosis. Ambient temperatures interact with
ingestion of toxin to cause heat stress. It is suggested
that usual weather conditions in New Zealand
temper the negative effects of the toxin. Higher
temperatures increase the levels of ergovaline in
pasture, and increase the sensitivity of livestock to
it. Heat stress in North Island cattle probably usually
results from the interaction of particular environmental
conditions with the grazing of perennial
ryegrass.
Keywords: endophyte, ergovaline, fescue
toxicosis, heat stress, Lolium perenne

Split-calving for production and profitJ. TAYLOR

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Calving cows in both autumn and spring (splitcalving)
has increased production and profit. Feed
demand has been changed to better suit the pasture
growth pattern on the farm. Demand has been
increased in winter when pasture can be grown,
and reduced in the summer dry period. Cow
numbers are still maintained through the spring to
utilise pasture efficiently as it grows. Split-calving
evens out seasonal variations, giving consistency
of production and cashflow. The work-load is also
spread, providing better employment conditions
and opportunities.
Keywords: feed demand, flexibility, profit, split calving

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Data collected for Bay Milk Products Ltd, using a
standard rate of growth technique, were analysed
to assess the effects of C, grasses on total pasture
and ryegrass growth rates. In the years when C,
grasses were prominent summer growth rates were
at their maximum but there was no evidence that
ryegrass growth rates were penalised by the C,
grass component in the same or subsequent years.
The results shoti that C, grasses are widespread in
the BOP and will continue to be an important part
of the BOP dairy pasture ecosystem. Several
suggestions are made on how to reduce the C,
grass component of the pastures, but it should be
recognised that agronomically useful types could
form a useful component of the sward in years
when climatic conditions during the summer period
are conducive to their vigorous growth.
Keywords: C, grasses, pasture growth, subtropical
grasses, summer production

Subtropical seed-bank of a Bay of Plenty dairy farmC.C. BELL

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An examination of the grass seed-bank on a Bay of
Plenty dairy farm in October 1994 found seed
numbers of all grass species were greatest in the
top O-50 mm of the soil profile and declined steeply
at two lower sampling depths (5 l-150 mm, 15 l-
250 mm). C, grass species comprised 58% of the
total viable seed in the upper sampling layer and
greater than 80% in the other two horizons. Panicum
dichotomiflorum was the dominant C, grass,
especially at the lowest sampling depth where it
comprised over 90% of the C, seeds and 78% of
the total seeds found. Previous management was
also an important influence on both the total seed
loading and its distribution within the soil profile.
Paddocks cultivated within the last 4 years had
more total viable seeds at all depths and more
Panicum dichotomiflorum seed at the deeper
sampling depths than paddocks not cultivated within
the last 4 years. The almost total absence of
perennial ryegrass (Loliumperenne) seed indicates
that it has a very short residual life in the seedbank.
Therefore, if ryegrass plants are not
maintained by vegetative propagation ryegrassbased
pastures are susceptible to invasion from
species that have a long residence time in the seedbank.
These results also show that seed-bank
surveys provide a method for assessing the potential
changes in botanical composition of pastures and
the geographical distribution of species such as
subtropical grasses that is independent of the
growing conditions at the time of sampling.
Keywords: C, grasses, Panicum dichotomiflorum,
seed-bank, subtropical grasses

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A series of composite case studies is used to explore
some effects of agricultural change on farmers.
The “grower”, the “opportunist”, the “tuner” and
the “passenger” are presented as representing a
range of true life scenarios, to illustrate how many
of the assumptions about the relationship between
the farmer and extension worker hinder the fostering
of change processes.
Keywords: change, emotions, extension workers,
farmers, human relationships, rationality, systemic change

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Establishment, botanical composition and production
of direct-drilled perennial ryegrass and tall
fescue were compared for two seeding rates in an
autumn-sown, grazed trial. Tall fescue (Festuca
arundinacea Schreb. cv. AU Triumph) was sown
at either 17 or 3 1 kg/ha and perennial ryegrass
(Lolium perenne L. cv. Grasslands Supernui) was
sown at 12 and 23 kg/ha on 12 April, 1990 all with
“Grasslands Pitau” white clover at 3 kg/ha.
Measurements of herbage mass and botanical
composition during the ensuing 2-year period
showed that there was no advantage in terms of
suppression of weed species or accumulation of
herbage mass of the sown species from sowing
more seed than that required to achieve a population
of 450-500 plants/m2 of either ryegrass and tall
fescue 6 weeks after sowing. A population of 150
white clover plants/m2 appeared to be adequate for
development of a balanced sward. Establishment
of fescue was slower than that of ryegrass but both
species developed to productive swards after
infrequent but close defoliation with dairy cattle in
the first spring and subsequent rotational grazing
by lactating dairy cows. Pasture establishment in
Northland is difficult because of shallow topsoils.
Direct drilling can preserve this fragile topsoil and
successfully establish alternative species such as
fescue as long as attention is paid to their
establishment requirements. Alternative species
may offer a solution to low feed availability of
ryegmss in the summer and poor survival of ryegrass
in poorly drained areas during the winter.
Keywords: direct drilling, Festuca arundinacea,
Lolium perenne, pasture establishment, seeding rate

The importance of a participatory approach to resolving issues of sustainable
agricultureT.G. PARMINTER, M.E. WEDDERBURN, and P.J. SPIJKERBOSCH

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A participatory study with Waikato livestock
farmers identified that lack of information to
implement sustainability objectives is limiting the
ability of some farmers to improve the condition of
their natural resources.
Keywords: evaluative matrix, information,
resource management, sustainable agriculture

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Recently many dairy farmers have sown turnips as
a summer feed for lactating cows. This paper reports
on a national survey of turnip crops in 1994-95, an
experiment on turnip yield responses to N fertiliser
and two short-term supplementary feeding trials.
Farmers had on average 4.3% of their farms in
turnips with a mean yield of 7.4 t DM/ha (range 0
to 15.2 t DM/ha) (n = 328). Barkant was the highest
yielding cultivar and mixtures yielded significantly
less than Barkant alone. Rainfall in November and
December but not January was positively associated
with turnip yield. Fertiliser N after sowing increased
turnip yield by 13.2 kg D/kg N, but fertiliser N at
sowing or P fertiliser in the three months to sowing
had no effect on yield. In contrast to the survey,
application of 25, 50, 100 or 200 kg N/ha after
sowing at TARS gave no significant increase in
total DM yield. Supplementing pasture with 3.6
and 5 kg turnip DM/cow/day at DRC and TARS
gave milksolids responses of 26 and 18%
respectively compared to pasture only. The survey
highlighted the variability of turnip yield, and
although many growers reached the economic
break-even point of 8-10 t DM/ha, there are less
risky alternatives to summer turnips such as
purchased maize silage and pasture from N-boosted
spring pasture.
Keywords: Barkant turnips, brassica, dairying,
farm survey, milksolids, nitrogen

Use of capital fertiliser and lime to improve pasture production in NorthlandM.B. O’CONNOR and B.J. HUNT

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Previous research in Northland identified the
requirements for phosphate and lime in pasture
development. Large capital inputs were necessary
(1.8-2.0 t superphosphate and 2.5-5 t lime/ha in
the first 12-18 months). More recently (1990-1993)
three trials have been conducted on typical
unimproved or improved hill country pasture in
Northland to investigate lime (rates and frequencies)
and phosphate (rates and forms)
requirements. Results show that capital inputs of
both fertiliser and lime are still very necessary in
Northland. Marked responses occurred in the trials,
with an average 40% increase to P and 16% increase
to lime. The need for a soluble fertiliser like
superphosphate was highlighted. In practice the
aim must be to get as much of the potentially high
producing land as possible into the soil test ranges
for maximising pasture production. Improvement
programmes need to be tailored to the individual
farm. In dairying, improvement programmes can
be completed relatively quickly (l-2 years) given
the current economic situation, but in hill country
the programme must of necessity be longer term
(4-5 years). Emphasis must first be on developing
the land with the highest potential. In time, areas
with lower productive potential can also be
considered for improvement, although alternative
sustainable land use options should also be
considered.
Keywords: capital inputs, fertilisers, lime, optimum
soil tests, phosphate, soil fertility

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Persistent and productive cultivars of limpograss
(Hemarthriu altissima (Poir.) Stapf et C.E. Hubb.)
are required if the species is to be useful in
Northland cattle systems. A study was undertaken
to investigate plant morphological traits, adaptation
and persistence of 8 accessions. A series of
abandoned research sites was revisited to determine
long-term persistence and adaptation. Trials were
established at 4 new sites throughout the northern
North Island to assess morphological variation and
plant survival. There was considerable variation in
morphological traits assessed and plant survival,
allowing scope for future selection. Bigalta used in
earlier research trials had largely failed to persist
under normal pasture management practices. Future
work should use the cultivar Floralta.
Keywords: adaptation, flowering, Hemarthria
altissima, leaf, morphological variation,
persistence, seed, stolon

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Within-year variation in herbage nutritive
parameters (digestibility (DOMD), crude protein,
soluble carbohydrate and fibre fractions) are
described for pasture samples collected from four
dairy farms with different soil and pasture
characteristics. Samples were collected at 2- to 4-
weekly intervals to reflect material likely to be
consumed by cows and analysed after freeze drying
by near infrared spectrophotometry (NIRs). Results
show large seasonal variations for most of the
nutritive parameters (e.g., digestibility (655SO%),
crude protein (13-32%), ADF (22-36%)). At times
these values exceeded or were inadequate to meet
the requirements of lactating cows. The implications
of pasture quality data for dairy farm management
and dairy cow productivity are discussed.
Keywords: carbohydrate, dairy cows, digestibility,
fibre, pasture quality, protein